1. Field of the Invention
The present invention relates to a roll feed apparatus for feeding intermittently a sheet-like blank material to a processing station on a step-by-step basis. More particularly, the invention concerns a roll feed apparatus which includes a main roll and a subroll for feeding intermittently a strip-like sheet material to one or more work stations such as metallic molds in a selective manner and which is suited to be incorporated in an automated manufacturing machines or other machine tools.
2. Description of the Prior Art
Many shortcomings have been noted in known sheet material feeding apparatus of the type described above in which a combination of a one-way clutch and a brake or a combination of a rotating cam and a cam follower is used for converting a continuous rotation input to an intermittent rotation output for driving intermittently the feeding roller. For example, it is difficult, not to say impossible, to feed a strip-like blank material stepwise by a predetermined quantity with a reasonable accuracy due to backlash in a gear train or a dimensional tolerance involved in implementing the cam and cam follower mechanism. The feeding operation may not be carried out at a high speed because jamming or deformation of the sheet material being stepwise fed will be then possibly involved. Troublesome and time consuming procedures are required for adjusting the feeding apparatus for different sheet materials having different thickness. Further, it has been impossible to vary a quantity of sheet material to be fed through a single feeding step in a continuous manner without interrupting operation of the feeding apparatus as well as associated tool or tools.